Subject: Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels
From: Lee Revell <rlrevell@joe-job.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>, Andrew Morton <akpm@osdl.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
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Date: Tue, 14 Sep 2004 20:35:15 -0400
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On Tue, 2004-09-14 at 10:54, Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> 
> > Another thing, I don't mean this to sound like a rhetorical question,
> > but if we have a preemptible kernel, why is it a good idea to sprinkle
>       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > cond_rescheds everywhere? Isn't this now the worst of both worlds? Why
> > would someone who really cares about latency not enable preempt?
> 
> two things:
> 
> 1) none of the big distros enables CONFIG_PREEMPT in their kernels - not
> even SuSE. This is pretty telling.
> 

I am not sure this means preemption is a bad idea, it just means there's
no point in enabling CONFIG_PREEMPT with the current kernel because it's
not enough of an improvement to make a difference for low latency
applications.

Lee

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